The brain consists of two types of cells: neurons and glial cells. Neurons are the cells that receive and send messages within the brain and make up what is referred to as gray matter (composed of cell bodies) and white matter (composed of axons). Glial cells are non-neuronal cells that provide support and protection for neurons. Astrocytes are a sub-type of glial cells in the brain and spinal cord. They retain their capacity for division throughout their life span, which makes them susceptible for transformation and contribute to the prevalence of astrocyte-derived tumors.
Brain tumors are caused by an abnormal and uncontrolled cell growth in the brain itself or as metastatic lesions of tumors in other organs. Low-grade astrocytomas, a class of malignant brain tumors, acquire their blood supply by co-opting existing normal blood vessels and propagating along them without initiating angiogenesis. This leads to diffuse invasion of tumor cells over long distances in the brain without formation of real tumor masses. As grade III astrocytomas progress to grade IV astrocytomas they grow in size, and to cope with the increased need for nutrients and oxygen they undergo an angiogenic switch. Glioblastoma multiforme (GBM) are the most malignant form of astrocytomas. They become highly vascularized and tumors appear more local than the low-grade astrocytomas. GBMs also retain the ability of invasive growth.
With respect to therapy, brain tumors that are beyond the reach of conventional therapies (e.g., surgery or radiation) and which grow diffusively to invade the brain are especially challenging to treat.
Inhibition of tumor angiogenesis is a therapeutic strategy, which has been used to treat a variety of malignant tumors. Systemic anti-angiogenic treatment of malignant brain tumors has shown to increase the number of satellite tumors in experimental animal models. There are reports according to which the treatment might even encourage tumor cells to more invasive phenotype.
WO 2009/136007 describes a peptide, CooP, which specifically homes to intracranial, early stage astrocytoma model that grows as islets and harbors co-opted tumor vessels in the brain. The peptide can be used in targeted delivery of therapeutic substances to invasive brain cancers or metastatic brain lesions and as a diagnostic tool.
However, new therapies for aggressive tumors are still needed and also new methods to recognize the most aggressive tumors from the less aggressive ones. Better diagnosis and treatment methods are needed, especially for invasive brain cancers and metastatic lesions of other tumor types in the brain.
It is an object of the present invention is to provide a method for determining the presence or grade of brain tumor in a patient.
It is a further object of the present invention to provide a method for treating brain tumor in a patient.
It is a further object of the present invention is to provide products, which can be used in diagnosis or treatment of brain tumors or metastatic lesions in the brain.